Coronary Heart Disease - An Overview
Coronary Heart Disease (or coronary artery disease) is a dreaded form of acquired heart disease that primarily affects adults and elderly age groups, leading to serious problems including heart attacks and acute coronary syndrome. Many preventable deaths every year are traced to coronary heart disease, making it a major public health challenge for governments and health agencies across the world.
Coronary Artery Structure
Before understanding coronary heart disease, you must know something about the coronary arteries themselves. The heart muscle requires energy and oxygen to continue pumping blood to various organs. Blood vessels called coronary arteries supply the heart with its fuel. Arising as branches off the main artery of the body, the aorta, these coronary arteries run along the surface of the heart, sending smaller branches into the wall of the heart chambers to provide it with blood supply.
There are 2 major coronary arteries, the main right (RCA) and left coronary arteries (LCA). The left coronary artery branches into two large divisions called the left anterior descending (LAD) branch and left circumflex (LCx) branch.
Because each of these 3 major branches supply a large chunk of heart muscle, the human coronary artery system is said to have three regions, each supplied by one of these branches. Each of these major branches has smaller divisions, which plunge into the heart muscle itself, delivering vital nutrients and oxygen to the pumping heart muscle.
For more detail about the coronary artery system, you can read this article about the "lifeline of the heart".
Coronary Heart Disease
When the coronary arteries become narrow as a consequence of the accumulation of atherosclerotic plaque along theor inner wall, blood flow to heart muscle becomes compromised. This leads to coronary heart disease, also called coronary artery disease.
This is a potentially serious condition because, when blood flow (and energy supply) to the heart muscle is lowered, the heart itself becomes incapable of pumping blood out to other organs. As an indirect consequence, every part of the body receives lesser blood flow than normal. An early indication of this deadly scenario inside the coronary arteries is the onset of angina pectoris, a form of severe crushing chest pain that occurs during exertion or excitement, and is a warning that coronary heart disease may have set in.
When coronary heart disease crosses a critical threshold, the region of heart muscle supplied by it sustains irreversible injury. This leads to a heart attack, where a portion of the heart muscle dies due to lack of blood flow. Unless treated as an emergency, this can cause sudden death. Even when effectively treated, there may be some amount of damage which cannot be restored back to normal.
This is what makes coronary heart disease such a serious issue.
Preventing Coronary Heart Disease
Prevention of coronary heart disease takes high priority in the healthcare administration of any population. An enormous amount of resources are spent on spreading awareness, educating the public, and implementing health reform that lowers the incidence and risk of coronary heart disease.
The causes of coronary artery disease are well documented. The most common are high cholesterol level, smoking, being over-weight, lack of exercise, high blood pressure, stress, and genetic factors including a strong family history of coronary heart disease. Most of these factors can be managed, and risk of coronary artery disease lowered.
For example, the simple act of smoking cessation has a significant and almost immediate effect on heart attack risk. Similarly, a modest amount of exercise such as walking for 30 minutes every day can reduce heart attack risk significantly. For good reason, coronary heart disease has been labelled a 'lifestyle disease' because it is caused by the adoption of a certain way of living which is unhealthy and subject to one's choice.
Mechanism of Coronary Heart Disease
Coronary heart disease is caused by the deposition of atherosclerotic plaque along the inner lining of coronary arteries. Due to an as yet unclear mechanism, probably related to inflammation of the endothelium of coronary arteries, excess cholesterol and fatty acids in the blood get layered along the artery wall producing plaque. Layer by layer, the plaque grows thicker and occludes more and more of the pipes that supply life-giving blood to heart muscle.
At any time, the plaque is prone to sudden rupture. This means the plaque bursts, releasing globules of fat and some particulate material into the coronary blood stream which can occlude smaller branches of it. But the more serious problem is that the suddenly roughened inner lining of the coronary artery caused by plaque rupture promotes blood clots to form inside the vessel.
When a blood clot forms inside an already narrowed coronary artery, it can abruptly block all blood flow through it, leading to a heart attack. The treatment of such a situation involves emergency measures to stablize the patient's condition, and then reinstitute blood flow through the coronary arteries by thrombolysis (clot busting), PTCA (cather angioplasty) or CABG (open heart surgery for bypass grafting of coronary arteries).
Coronary heart disease is treatable, but the treatment is costly and complex. Coronary heart disease is also preventable through common sense measures. This is easier, less expensive, and desirable.